How do I find out the development potential of my lot?

Posted By: Neil Ayton Maintenance,

Looking to expand your portfolio? If you’re sitting on a plot of land in Seattle, you may be wondering how to figure out its development potential.

Having a crystal clear idea of what you stand to gain from development lots is essential. After all, when you’re putting in so much time and money into an enterprise you need to guarantee a great return on investment.

At Kanso Homes, we have an experienced team of financial analysts, architects, project managers and contractors. We help our clients get the most out of a residential redevelopment project.

So where should you start? Here’s our step-by-step guide to figuring out the development potential of your lot.  

Discovering the potential of development lots: a step by step

Step 1 – Find your zoning

Go to and enter the address of your lot to see the zoning type of your lot. In Seattle, residential lots are designated as either single-family or multi-family lots. Whichever category your development lots fall into, you have the option to add an additional dwelling unit (ADU). Residential Small Lot (RSL) zones are a new zoning designation since 2019 and replaced a lot of SF5000 lots in Seattle. They have slightly different development rules than traditional single-family zone lots, mainly higher density!  Low Rise (LR) zones form part of Seattle’s multi-family zoning and include properties like townhouses and rowhouses.

Step 2 – Gather the info you need to calculate how much you can build on a lot

So what information do you need to calculate the size and number of dwellings you can build on your lot? Here are the facts and figures you need to get your head around.

Zoning type

You found out your zoning type by visiting the website above. Now it’s time to learn a little more about what that zoning type means.

Here’s a quick summary of each residential zone and rules around redevelopment.

Single-family zone:

Up to two ADUs (for the second ADU, green building requirements may apply)

Maximum size of 1,000 square feet per ADU

RSL zone:

One unit per 2,000 square feet of lot area

Maximum size of 1,000 square feet per ADU

Floor area ratio (FAR) 0.75 is used to calculate allowed square foot. E.g 6000 sq ft lot X 0.75 = a 4500 sq ft building

Multi-family LR zone:

One ADU for every 1,300 square feet of lot area

No limit to the number of units you can build

Lot size

As you can see from the zoning type redevelopment regulations, it’s important to know exactly the size of your lot and the square footage of any existing dwellings.

Floor area ratio (FAR)

Floor area ratio is: the total floor area of buildings on your lot ÷ the total lot area. This number is displayed as a decimal and it tells you how developed your lot already is. It’s important to know this because some zoning types have a FAR limit.

Step 3 – Skip the tricky math to calculate development potential

If math isn’t your strong suit, leave the calculations to us. Use our Kanso Homes tool to find out how many square feet you are allowed to build on a particular lot. 

Why not get a helping hand from Kanso Homes at every stage of your development?

Staying on the right side of building laws, designing and building the ideal property, and making a healthy profit on your redevelopment is a challenge.

Without a wealth of experience in the process, there will be obstacles and mistakes along the way – both of which can be very costly.


At Kanso Homes we help property owners, landlords and investors avoid those redevelopment problems.

Our team covers all the bases – from financial planning through to construction – helping you to minimize risk and maximize the value of your development lots.

Get in touch at to find out more.